Rolling mill gage control actuator system



June 30, 1970 J, 5, STRANGE 3,517,531

ROLLING MILL GAGE CONTROL ACTUATOR SYSTEM Filed Nov. 5, 1967 2 Sheets-Sheet 1 INVENTOR. JOHN V S. STRANGE ATTORNEYS.

June 30, 1970 J. s. STRANGE 3,517,

ROLLING MILL GAGE CONTROL ACTUATOR SYSTEM Filed Nov. 5. 196'? 2 Sheets-Sheet 2 FIG. 2

INVENTOR. JOHN SSTRANCE ATTORNEYS.

United States Patent 3,517,531 ROLLING MILL GAGE CONTROL ACTUATOR SYSTEM John Sherman Strance, Dover, Mass., assignor, by mesne assignments, to Gulf & Western Industrial Products Company, Grand Rapids, Mich., a corporation of Delaware Filed Nov. 3, 1967, Ser. No. 680,412 Int. Cl. B21b 37/02 US. CI. 72-16 3 Claims ABSTRACT OF THE DISCLOSURE A gage control actuator system for a rolling mill in which the rolls are adjustably separated by a wedge which in turn is actuated by a thickness gaging system. Hydrostatic hearings on the surfaces of the wedge provide an oil film which separates the surfaces of the wedge from the adjacent surfaces of the mill so that an essentially frictionless system is obtained.

This invention relates to rolling mills and, more particularly, to a rolling mill gage control system for controlling With improved accuracy the thickness of a rolled product.

Rolling mills have employed heretofore a gage control system to vary the spacing of the rolls. This system normally has employed the use of screw downs which may be actuated by a motor to adjust the spacing between the rolls. However, several problems have been experienced with the screw down type of device. The major problem has been the relatively slow response of the screw down device in adjusting for changes in thickness of the product being rolled. Several reasons for this are apparent. First and foremost is the relatively large cornpressive forces necessarily present in the screw down device which generate frictional forces that adversely affect the sensitivity of the device. The result is that the device is insensitive to small changes in thickness of the product being rolled. Moreover the compressive forces magnify the problems of wear on the mating surfaces of the device and require, particular attention to be given to the coefficient of friction of the materials employed in the control system.

One approach which has attempted to solve this problem has been the use of a nylon surfaced wedge which provides a means for controlling the roll spacing. However, even in the case of the nylon coated wedge, the problems of wear and the coefiicient of friction are present as are also the problems of slow response to signals indicating a change in the thickness of the roll product. Thus, this latter approach has diminished the problems but has not provided a complete solution.

It is an object of this invention to provide a new and improved gage control system for controlling the thickness of a product being rolled in a rolling mill. In accordance with the primary aspect of this invention, direct surface contact between the adjusting surfaces is eliminated and the frictional forces which have heretofore resulted in a slow response of the system are virtually eliminated.

A more specific aspect of the invention is the provision of a roll spacing wedge employing a hydrostatic bearing on two surfaces thereof with the oil film eliminating the fricitional forces and the movement of the wedge being in accordance with a thickness gaging device.

Another object of this invention is to provide a rolling mill gage control actuator system which is quick reacting and which will hold the rolling mill rolls at any de sired opening so that a high quality product may be produced.

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A further object of this invention is to provide a rolling mill gage control system in which the problems heretofore experienced with wear in the system are virtually eliminated.

Other objects and advantages of the invention will become more apparent upon a complete reading of the following description when read in conjunction with the attached drawings.

Referring to the drawings wherein like reference numerals indicate like parts in the various views:

FIG. 1 is a schematic illustration, in perspective, of a rolling mill employing the gage control system of the present invention.

FIG. 2 is a section through the wedge and illustrates schematically the hydrostatic bearing system.

Referring now to the drawings wherein the showing is for purposes of illustrating a preferred embodiment of the invention only and is not intended to be limiting, FIG. 1 illustrates somewhat schematically, a rolling mill indicated by the reference numeral 10 comprising a frame 12 supporting a pair of rolls 14, 16. The rolls are supported at opposite ends by bearings 18, 19 supported in the frame 12. A conventional screw down device 20 is employed to provide a force on the upper roll 14 and force the roll 15 toward the lower roll 16.

Although the conventional rolling mills heretofore have employed the lower roll 16 as a fixed roll, it is contemplated by this invention that an adjustable gage control system will be associated with the lower roll 16 to provide a variable adjustment between the two rolls 14, 16. Although for purposes of illustration but a single one of these adjustable devices are illustrated, it is to be understood that one such device would be employed at either end of the rolls 14, 16.

The adjustable gage control system comprises a support pad or runner 30 which supports on its upper surface the bearing 19. The lower surface 32 of the pad 30 is formed at an angle which is designed to cooperate with an angled surface 34 on an adjusting wedge 36. The *wedge 36 is in turn supported by surface 37 on a bearing surface 38 formed on the frame of the rolling mill. It is contemplated by the principles of this invention that the mating surfaces between the wedge 36, the frame of the mill and the pad 30 will employ hydrostatic bearings to reduce the frictional forces which would normally be present in this arrangement.

Referring now to FIG. 2, a typical hydrostatic bearing arrangement suitable for the wedge adjustment is illustrated. It is to be appreciated that other forms of hydrotsatic bearing surfaces may be employed but it is preferred that a flat pad bearing design be employed. As shown in FIG. 2, the pad 30 includes a recess groove 40 which is formed in the surface 32 and which opens toward the surface 34 on wedge 36. The recess may take a variety of configurations but is designed to contain a lubricant which is supplied through passages 42 formed in the pad 30.

A similar design is employed at the mating surfaces between the wedge 36 and the frame 12. Thus, a recess groove 46 is formed in the surface 38 on frame 12 and opens upwardly toward the lower surface 37 of the wedge 36. Passages 48 in the frame 12 provide a path for the lubricant to reach the recess 46.

It will be noted that the recesses 40 and 46 extend across a substantial portion of the adjacent surfaces of the wedge 36. In this manner, a substantial area of fluid support is provided by the hydrostatic bearings which eliminates any metal-to-metal engagement between the relatively moving parts.

To supply fluid to the hydrostatic bearings, any of a number of systems may be employed. FIG. 2 illustrates schematically one such system in which a source of pressurized lubricant 50 is supplied to a supply manifold 52. The manifold 52 may be used to supply a plurality of hydrostatic bearings. For example, the passages 42 and 48 may both be connected with the same supply manifold. From the supply manifold, the pressurized lubricant passes through a compensating element which may be employed, depending on the particular system, to provide the correct pressure level to the bearing surfaces. From the compensating element, the lubricant passes through passags 42 and 48 to the recess grooves 40 and 46. The particular configuration of the grooves 40 and 46 may, of course, be varied; however, it is necessary that some form of recess grooves be present to contain the pressurized lubricant between the mating surfaces. The lubricant supplied to the grooves 40, 46 will fill the grooves and flow across the area between the grooves to produce an oil film which exerts a separating force between the adjacent surfaces 32, 38 and the wedge 36. Some of the lubricant will, of course, spread outwardly beyond the outer walls of the grooves 40 and 46 and provide some reduced bearing support; however, the greater bearing support forceswill be within the area defined by the recess grooves 40, 46.

In combination with the wedge 36 and its associated hydrostatic bearings, it is contemplated that an actuator 60 will be used with each wedge. The actuator may be any one of several types including a hydraulic piston with a servocontrol, a hydraulic motor with servocontrol or an electric motor, as well as other types. The actuator is operatively connected with a conventional thickness measuring gage 64 with the output of the thickness gage being employed to control the actuator which in turn adjusts the position of the wedge 36.

The above-described rolling mill gage control system operates in the following manner. The rolls 14, 16 may be adjusted by the screw down device 20 and a sheet of metal M introduced between the rolls. As the rolling mill operation is performed, the thickness gage 64 continuously measures the thickness of the rolled product to determine if the desired thickness is being obtained. In the event that a variation in the thickness is sensed by the gage 64, an appropriate signal will be transmitted to the actuator 60 which in turn will adjust the position of the wedge 36. Movement of the wedge 36 will, through the mating inclined surfaces 32, 34, vary the spacing between the rolls 14, 16 and thereby provide compensation for the thickness of the roll product.

It will be appreciated that the response of the wedge 36 in adjusting the spacing between the rolls 14, 16 is dependent only on the sensitivity of the gage 64 and the inertia inherent in the system since there is no frictional engagement between the wedge and the frame 12 or the pad with the hydrostatic bearings providing an essentially frictionless oil film between the surfaces 32, 38 and the wedge 36.

A particular advantage of the described system is that the selection of the materials used in the pad 30 and wedge 36 may be made without regard to their coefficient of friction since the frictional forces have been virtually eliminated. This, in turn, permits the use of the wedge as a very simple means for adjusting the force on the rolls of the rolling mill. Since the force on the rolls is determined by the normal force on the mill divided by the angle of wedge surface 34, the force applied to the mill can be adjusted simply by varying the angle of the wedge.

Although the invention has been described in connection with the rolling of a sheet of metal, it will be appreciated that the invention has equal application in the rolling of any type of product in which the uniformity of the thickness is a consideration. It is also to be understood that the particular configuration of the wedges 36 may be varied. For example, a plurality of wedges may be employed at each end of the rolls 14, 16. Moreover, the movement of the wedges rather than being along a line generally perpendicular to the longitudinal axis of the rolls may be along a line parallel to the rolls, or at some angle to the rolls.

Other modifications and changes in the disclosed embodiment will suggest themselves to those having ordinary skill in the art so that, although the present invention has been discussed in connection with a certain structural embodiment, it is to be appreciated that this disclosed embodiment is not intended to limit the spirit and scope of the present invention as defined in the appended claims.

Having thus described my invention, I claim:

1. In a rolling mill having a pair of rolls supported in a frame and adapted to receive a piece of material therebetween, means supporting at least one of said rolls on the frame for movement toward and away from the other of the rolls and an actuator system for controlling the movement of said one roll, said actuator system including an actuator and a thickness gage for measuring the thickness of the material being rolled and operative to transmit a signal to the actuator, the improvement comprising:

wedge means slidably supported on said mill frame,

said actuator being operatively connected to said wedge means, bearing pad means connected to said one roll, said wedge means, bearing pad means and frame being arranged to cooperatively support said one roll with said wedge means being positioned between said bearing pad means and said frame, and

hydrostatic bearings defined between said wedge means and said frame and said wedge means and said pad means whereby an oil film separates the mating surfaces of said wedge means, bearing pad means and frame.

2. The improvement of claim 1 wherein said wedge means includes an angled surface on one face thereof;

an angled surface on one face of said pad means mating with said angled surface on said wedge means, recess grooves in one of said mating surfaces, and

a source of pressurized lubricant in communication with said grooves whereby a lubricant film separates said mating surface.

3. The improvement of claim 2 wherein said hydrostatic bearing between said wedge means and said frame comprises recess grooves in one of the surfaces on said wedge means and said frame, and

a source of pressurized lubricant in communication with said grooves whereby a lubricant film separates said wedge means from said frame.

References Cited UNITED STATES PATENTS 3,064,509 11/1962 Ford et a1 72243 3,197,986 8/1965 Freedman et a1. 72l6 3,271,086 9/1966 Deffrene 3085 3,355,925 12/ 1967 Barnikel et al 72244 3,418,025 12/1968 Hucks et a1 3085 FOREIGN PATENTS 760,698 6/1967 Canada. 995,208 6/1965 Great Britain.

CHARLES W. LANHAM, Primary Examiner B. I. MUSTAIKIS, Assistant Examiner US. Cl. X.R. 

